The present invention relates to ultrasound imaging systems, and more particularly, to an ultrasound imaging system for generating a high resolution, three-dimensional image of an object.
Prior art relating to ultrasound imaging of the body is disclosed in the following patents. U.S. Pat. No. 4,992,989 entitled "Ultrasound Probe for Medical Imaging System", U.S. Pat. No. 5,070,879 entitled "Ultrasound Imaging Method and Apparatus", U.S. Pat. No. 5,318,027 entitled "Stack-Connectable Ultrasound Probe, Ultrasound Imaging System and Diagnostic Sonography System", U.S. Pat. No. 5,211,168 entitled "Moving Electrode Transducer for Real Time Ultrasound Imaging for use in Medical Applications", U.S. Pat. No. 5,269,307 entitled "Medical Ultrasonic Imaging System with Dynamic Focusing", U.S. Pat. No. 5,331,947 entitled "Inflatable Sheath for Introduction of Ultrasonic Catheter Through the Lumen of a Fiber Optic Endoscope", U.S. Pat. No. 4,773,268 entitled "Multiple Transducer Ultrasound Probes", U.S. Pat. No. 5,315,999 entitled "Ultrasound Imaging System Having User Preset Modes", U.S. Pat. No. 4,434,662 entitled "Ultrasonic Image Generating Apparatus", U.S. Pat. No. 4,457,175 entitled "Insonification Apparatus for an Ultrasound Transmission System", U.S. Pat. No. 3,979,711 entitled "Ultrasonic Transducer Array and Imaging System", U.S. Pat. No. 5,339,282 entitled "Resolution Enhancement for Ultrasonic Reflection Mode Imaging", U.S. Pat. No. 4,269,066 entitled "Ultrasonic Sensing Apparatus", U.S. Pat. No. 5,176,142 entitled "Endoscopic Ultrasound Probe with Take-up Cable Mechanism", U.S. Pat. No. 5,150,715 entitled "Ultrasound-Imaging Diagnostic System", U.S. Pat. Nos. 4,222,274 and 4,317,369 entitled "Ultrasound Imaging Apparatus and Method", U.S. Pat. No. 5,311,095 entitled "Ultrasonic Transducer Array", U.S. Pat. No. 5,320,104 entitled "Transesophageal Ultrasound Probe", U.S. Pat. No. 4,463,608 entitled "Ultrasound Imaging System", U.S. Pat. No. 4,817,616 entitled "Auto Switch Biplane Prostate Probe", U.S. Pat. No. 5,088,500 entitled "Ultrasound Finger Probe and Method for Use", U.S. Pat. No. 4,742,829 entitled "Intracavitary Ultrasound and Biopsy Probe for Transvaginal Imaging", U.S. Pat. No. 4,819,650 entitled "Biplane Probe Including Centerline Highlighting", and U.S. Pat. No. 4,154,113 entitled "Ultrasonic Imaging System".
A typical ultrasound imaging system is a hand-held phased array that generates a crude image. The imaging system broadcasts short bursts of ultrasonic energy and receives the energy on an array of ultrasound transducers. The transducers are carefully shaped to be wide enough to form a narrow antenna beam in one dimension. In the other dimension, the transducers are treated as a phased array to generate a number of sonic antenna beams forming a crude image of an area of the body. A typical pulse has a bandwidth of 5 megahertz permitting the range resolution to be on the order of 300 microns. However, the resolution in cross range is generally much less, resulting in a blotchy image that is difficult to visualize.
Difficulties that limit the ultrasound imaging system are the narrow pulse used for imaging and the two dimensional image derived from the three-dimensional object that is imaged. The sound absorption in the body tissues is enough that higher frequency sounds are absorbed before they return to the sensor from distant body pans. The use of the imaging system requires the development of user skills regarding interpretation of the images in terms of the anatomy that is imaged and the possible pathologies instead of providing an easy to interpret three-dimensional image.
It has been determined that if the energy pulse that is used to sense the body structure is made longer, the amount of energy that is generated may be made many times larger. With the larger total energy, the problems resulting from energy absorption by the body can be overcome, permitting detailed imaging of deep body parts.
Therefore, it is an objective of the present invention to provide for a three-dimensional ultrasound imaging system that minimized problems caused by energy absorption by the body, thus permitting detailed imaging of deep body parts.